The present invention relates to a data processor which is incorporated in a word processor, a calculating machine, etc.
In general, a conventional data processor incorporated in a word processor, a calculating machine, and the like includes a display apparatus consisting of a CRT (Cathode-Ray Tube), a main controller for controlling image data which includes characters, figures ad the like displayed on the display apparatus, and a key board which is operated by the user to input the image data. The display apparatus has a display unit which is rectangular in shape the orientation of which is fixed, that is, in either a vertically elongated direction or a laterally elongated.
Having the display unit orientation fixed in either a vertically elongated or a laterally elongated direction creates a number of, problems.
For example, if display unit is fixed in the laterally elongate direction so as to have a laterally elongated screen, a larger number of characters can be displayed in the lateral direction documents of A4 size generated in the lateral elongation are present as a whole A4 page of data at one time.
However, various other layouts and sizes of documents exist, such as A4, B4 and the like with two directions for each document that is, a laterally elongated direction and a vertically elongated direction. In making a document for example, of size A4 and vertically elongated orientation the total number of lines of a page which can be displayed by the display unit is not sufficiently large to display the whole A4 page of data on the screen. This leads inefficient document creation.
In recent years, there has been proposed a data processor including a display apparatus where the display unit can be pivoted to either a vertically elongated position and a laterally elongated position. In such a data processor, however, the user must use the key board to set an onscreen format in a vertically or laterally elongated direction, and such an operation of setting a onscreen format is an annoying task to the user.
As related art to the present invention, for example, U.S. Pat. No. 4,267,555 discloses a rotatable raster scan display which includes a CRT display apparatus which can switch a onscreen display between a vertically elongated layout and a laterally elongated layout. The rotation of the CRT display apparatus is turned on or off by a control switch to selectively control a length of horizontal scanning lines and a length of a sweep corresponding to the direction of the CRT display apparatus. U.S. Pat. No. 4,542,377 also discloses a rotatable display work station which includes a CRT display apparatus which can switch a onscreen display between a vertically elongated layout and a laterally elongated layout and in which two kinds of character generators are provided. Character display begins with characters at the upper left portion of a CRT screen in a lateral (horizontal) mode.
Additionally, there are several similar apparatus disclosed in Japanese Unexamined Patent Publications SHO/59-62891 and SHO/62-173509. The former is an apparatus having a picture display which is rectangular in shape and which can be displaced from a vertically elongated position to a laterally elongated position, and vice versa. Either the vertically elongated position or the laterally elongated position of the picture display is detected, and accordingly, the picture display presents a vertically or laterally elongated picture. The latter publication discloses an apparatus having a display unit and a rotary mechanism for turning the display unit itself, in which turning of the display unit is detected to produce a detection signal, and the contents stored in an image memory is turned and rewritten in accordance with the detection signal. However, the contents remain in their current display position if the turning brings about a disallowable display.